onPointerHover method
Used by the Listener callback to display the pen if desired
Implementation
@override
void onPointerHover(PointerHoverEvent event) {
if (!value.supportedPointerKinds.contains(event.kind)) return;
temporaryValue = value.copyWith(
pointerPosition:
event.distance > 10000 ? null : _getPointFromEvent(event),
);
}